Byzance et les Arabes. Tome I, La dynastie d'Amorium (820-867), by Alexander A. Vasiliev, in 468 bookmarked and searchable pdf pages. This is the first volume (Brussels, 1935) of a three-volume series dealing with Byzantium's relations with the Arabs during the period 820-959. Volume 1 covers the Amorium dynasty (820-867) and the reigns of emperors Michael II, Theophilus, and Michael III. The Appendices for this volume have extensive French translations of relevant Arab sources and also notes by M. Canard and H. Gregoire. Compiled by Robert Bedrosian.

Volume 2, which covers the Macedonian dynasty (867-959), is not currently available.  Internet Archive has Volume 3, by Ernst Honigmann, which is devoted to the historical geography of Byzantium's eastern border during the period 363 through 1071: Die Ostgrenze des byzantinischen Reiches: von 363 bis 1071 nach griechischen, arabischen, syrischen und armenischen Quellen.

Vasiliev originally published the first two volumes in Russian (Petersburg, 1900, 1902). Both volumes are available for reading online in Russian: Византия и Арабы [Byzantium and the Arabs], at vostlit.info.